A Supersized Volcano

By Susan K. Lewis

Posted 09.26.06

NOVA

In 1949, when a Dutch geologist discovered massive deposits of volcanic rock around Lake Toba on the Indonesian island of Sumatra, scientists knew they were onto something big. The thousand-square-mile area, it turned out, was a giant caldera once filled with steaming volcanic ash and pumice. Toba's eruption roughly 74,000 years ago was so immense it was deemed a "supervolcano." Here, see how it dwarfs even disastrous "regular-sized" eruptions of our time.